I am very impatient

Came from BF Resynced, having a hard time adjusting in levelling up/combat as it is very easy in BF. I can run through guards in BF while I run literally from the ones in shadows.

I want to love this game cause I bought it in full price lol so is there any tips on how to make life easier/levelling up faster and easier? Which should i upgrade first?

I am not a hard time gaymer so pls help